Nowadays, there exist a large number of solutions for gas sealing arrangements in connection with oil and gas production. It is important that processed chemicals, solvents and other fluids are kept as pure as possible during all phases of handling and supply, since any contact with contamination will increase the risk of faults in the produced product. In systems which handle fluids under high pressure, each connection link represents a risk of leakage or penetrating contamination. A measure against such unwanted events can be the application of a combination of solutions which as a whole reduce the risk. An example for such a combined solution within production tubing of oil and gas is given in U.S. Pat. No. 5,090,871 A, which discloses a flange based coupling with dual o-ring seals and clamping device, and also a test port for detection of leakage by use of a sensor device. U.S. Pat. No. 163,148 B describes a similar sealing system which restricts passage of oil, gas, steam, smoke and flames.
However none of these publications mentions active use of coupling flanges which are adapted according to standard compact flange coupling (CFC) and which are shaped tapered in order to achieve a pre-tensioning pressure between the two connection parts. Use of such coupling flanges has shown to significantly lower the risk for said leakage or penetrating contamination, and the combination CFC, clamping device and sealing ring(s) makes the present invention particularly suited for fluids under high pressure.
Said references do not mention either active use of distinct geometrical shapes on the clamping surfaces in order to achieve more efficient, safer and simpler connecting of connection parts.
It is very important for such a connector that the external loads do not go through the seals. By application of for example usual ASME-flanges a considerable part of the external load runs through the seals, and thus can normally not be used to take external loads.
In connectors of said type, there occur even strains in the sealing area in that the two connector parts move away from each other as a consequence of elasticity in flanges and clamping arrangements. By having pre-tensioned the flanges in two surfaces close to the seals, we achieve a relief of this pressure instead of a strain in this area.